This disclosure is one of a series related to pultruded composites and particularly to their use as structural members. Several of the previous disclosures related to a high-voltage transmission tower which utilizes the same basic members that are disclosed herein. The transmission tower of the prior disclosures, including the parent patent to this Continuation-in-Part application, utilized four continuous legs or posts at the corners of the tower, the legs being outwardly concave to form the overall silhouette of the tower. Each leg was a continuous pultrusion having a pair of orthoginal internal channels which seated the orthogonally related bifurcated ends of pultruded cross members inserted therein through openings cut through the side wall or skin of the leg.
The transmission tower demonstrated the practicality of creating very strong joints between large composite structural members irrespective of the complexity of the angles at which such members met. The same basic construction is used in the instant disclosure, with the leg members of the prior disclosure used as the I-beams of the heavy construction applications of this disclosure. Similarly, the cross members of the prior disclosures relating to transmission towers are parallel to the support members of the instant disclosure, which fit into the internal voids of the I-beams. The same locking mechanism is used, comprising a block which slides through the hollow cross member to its bifurcated end to prevent the tines from opening once they have expanded.
One of the principle significant features of this disclosure is the use of pultrusions to form large structural members used in construction projects of about the largest scale attempted for steel structures. Trusses are disclosed supporting up to 10,000,000 pounds with nothing more than composites in the assembly.
Having gone this far with composites it is apparent that there is little that could not be done structurally with composite pultrusions if strength is the primary criterion. The disclosed system is the essence of simplicity. For the I-beam and the mating support member, two pultrusion dies only are required. With these two dies, one creating the I-beam with an internal configuration which mates with the external configuration to be machined into the other pultrusion, any brace, truss or frame structure can be made with intersections between the I-beams and the supporting members occurring at virtually any angle.